Rust inhibiting composition



UnitedStates Patent RUST INHIBITING COMPOSITION Robert W. Schrum,Lansing, Ill., assignor to Sinclair Refining Company, New York, N.Y., acorporation of Maine 4 Claims. (Cl. 252-495) This invention relatesto'new compositions of matter and in particular relates to definedoxidate-containing compositions. The compositions of the presentinvention are especially useful for rust inhibiting purposes,particularly in petroleum applications.

Parafiin wax oxidates are known to be excellent rust inhibitors fordistillate fuels, e.g., gasoline. Typical of these oxidates are oxidatesof crystalline petroleum wax, such as slack wax or other paraffin wax,and oxidates of foots oil fractions such as are disclosed in pendingapplication Serial No. 410,709, filed February 16, 1954, of John WalterNelson, now U. S. Patent No. 2,776,309. Oxidates of petroleum waxcomprise oil-soluble, water-insoluble C acids and oxygenated acids whichare solid in their normal state while oxidates of foots oil fractionsare waxy solids which are oil-soluble, water-insoluble and comprisemonoand di-basic acids, hydroxy acids, normal esters and otheroxygen-containing organic compounds and hydro carbons in a wide range ofmolecular weights. Before use crude oxidates normally are purified toremove inorganic compounds formed by catalysts, remove low molecularweight corrosive acids, recover dibasic acids and to improve color andodor. An advantageous purification pro cedure is disclosed in pendingapplication Serial No. 410,711, filed February 16, 1954, of John WalterNelson, now US. Patent No. 2,723,988, as is applied to foots oiloxidates.

The use of oil-soluble aromatic sulfonates as rust inhibitors forpetroleum applications such as 'pipeline products transmission also iswell known. Particularly advantageous examples of such sulfonatesinclude the alkali metal, alkaline earth metal and ammonium mahoganysulfonates and neutralized sulfonated bottoms from the manufacture ofdodecylbenzene. Frequently mixtures of the oxidates-and oil-solublearomatic sulfonates are employed, especially when synergistic activityof the resulting mixture is evidenced. Thus, in the pen-ding applicationSerial NO. 464,873, filed October 26, 1954, of Ray C. Smith, it isdisclosed that mixtures of foots oil oxidates and ammonia neutralizedsulfonated bottoms from the manufacture of dodecylbenzene are especiallyadvantageous rust inhibitors for petroleum applications in thatsynergistic a'ctivity'is evidenced.

For convenient and satisfactory use of the oxidates as rust inhibitorsin distillate fuels or other petroleum products, either alone or inadmixture with oil-soluble aromatic sulfonates, a concentrate in asuitable solvent which can'be conveniently added to the distillate fuelto be inhibited is desirable. Such a concentrate must have a low pourpoint, advantageously about 20 F. and below, to maintain low temperaturefluidity. Moreover, the resulting concentrate must be clear and shouldbe of big flash point, e. g., above about 110 "-It has been discoveredthat solutions containing paraffin wax oxidates such as foots oiloxidates and crystalline waxoxidate's can be-produced which are clearand are characterized by low. pour points. It hasalso been discoveredthat compositions comprising solutions of parafiin 2,881,140 9 PatentedApr.7,"19 59 wax oxidates in a solvent can be incorporated in petroleumdistillate fractions to impart anti-corrosive properties to thedistillate fractions. It has also been discovered that concentratescontaining oil-soluble aromatic sulfonates and the defined parafiin waxoxidates such as foots oil Oxi-- dates and crystalline wax oxidates,having low pour points; can be produced. These advantages are obtainedby the addition of a small amount of a substantially dehydratedpartially oxidized microcrystalline wax, i. e. petrolatum; to a solutionof an oxidate alone or an oxidate and oilsoluble aromatic sulfonates indefined solvents effective to lower the pour point of the resultingsolution.

Thus compositions of this invention comprise, in oneembodiment, clear,bright concentrates of parafiin wax'f oxidate such as an'oxidate of afoots oil fraction or a crystalline parafiin wax oxidate and a smallamount of a substantially dehydrated partially oxidized microcrystallinewax in a suitable solvent. More particularly, these novel compositionscomprise essentially about 5 to 65} weight percent of the definedoxidate, about 0.1 to 4 weight percent of a partially oxidizedmicrocrystalline wax and about 35 to weight percent of a solvent. lnanother embodiment, the compositions comprise clear, bright concentratesof the defined oxidate, oil-soluble'aromatic sulfonates and a smallamount of a partially oxidized microcrystalline wax in a suitablesolvent. Compositions including the defined sulfonates generally containthe respective components as follows: about 5 to 15' weight percent ofoxidate, about 15 to 30 weight percent of the sulfonated material, about0.1 to 4 weight percentof partially oxidized microcrystalline wax andabout 50' to 80 weight percent of a solvent. The compositions describedalso can include a small amount of a polar solvent to facilitatesolubility of the defined oxidate and to aid instabilizing thesolutions. The polar solvents which can be employed are high boilingalcohols, ketones, ethers, or Cellosolves, which are ethylene glycolalkyl-substituted ethers, of a'boiling point of at least2l2 F. Methyland butyl Cellosolves are particularly advantageous. The polar solventgenerally is used inamounts equivalent to about 0.1 to 2 or more weightpercent of the total composition.

In general the compositions of the present invention are prepared byaddition of the components in any order. Desirably, the oxidates aredispersed in the hydrocarbon solvent at a temperature of about roomtemperature to C. while stirring and then thesulfonates, if any, and themicrocrystalline wax are added and the tempera-. ture maintained untilsolution is complete. In the alter* native, the oxidate andmicrocrystalline wax can be PFC! mixed and added to the solventconjointly. Of coursewhere the sulfonate iscmployed it too can bepremixed with the Oxidized microcrystalline wax and the oxidate and theentire mixture then blended into the solvent.

The microcrystalline. wax oxidates useful in this in! vention areobtained by partially oxidizing microcrystals linewax fractionsobtained-from various crudes, i. e., Mid-Continent, mixed baseor-paraflinic, according to known processes. The" oxidates of"microcrystalline .wax advantageously are prepared by the oxidationprocedure disclosed in' the patent of John Walter Nelson No. 2,610,974,though any other known process can be employed if desired. Thus, amicrocrystalline wax can be contacted with oxygen, either in the pureform or in the presence of diluents, such as in air, at an elevatedtemperature in excess of 100 C. Advantageously, an oxidation catalyst,such asammonium vanadate, potassium permanganate-or various manganesesalts, is employed in the process. The microcrystalline wax is not com;pletely Oxidized as the microcrystalline wax oxidate em: ployed in thepresent invention must have a saponifica I tionnumber within certaindefined limits. For this in;

mass, indicate the saponification number is about 15 to 200. Uponpurification as by a. dilute acid wash, the oxidates evidence asaponification number within the necessary range, i.e., about 10 toabout 150. The oxidate is then dried, for example, by air blowing, untilthe water content is at least below about 1.0 percent. The resultingpartially oxidized microcrystalline wax having a saporufication numberof about 10 to 150 and being substantially dehydrated, i.e., having awater content of less than 1.0 weight percent, is employed in thepresent invcntlon.

The parafiin wax oxidates are used in amounts of about 5 to 65 weightpercent, and preferably 15 to 65 percent, based on the composition.Foots oil oxidates are obtained by the controlled oxidation of foots oilfractions obtained from slack wax. The fractions obtamed from aresweating step in the sweating of slack wax are particularlyadvantageous; fractions obtained by the solvent, e.g., methylethylketone, de-oiling of slack wax are also useful. Advantageous foots oilfractrons to be oxidized are characterized by a melting point within therange of about 80 to 120 F., an oil content of about 3 to 30 percent andan API gravity of about 30 to 45.

The foots oil oxidates are prepared by subjecting a foots oil fractionto large amounts of air or oxygen at an elevated temperature, i. e.,above about 250 F., in the presence of about 0.2 to 1.7 weight percentof an oxidation catalyst, e.g., potassium permanganate, for a period oftime sufi'icient to effect substantially complete oxidation of the footsoil. For example, a foots oil fraction obtained as described above andhaving a melting point of about 80 to 120 F., an oil content of about 3to 30 percent and an API gravity of about 30 to 45 is oxidized withoxygen in the presence of potassium permanganate. The reaction iscarried out at about 250 to 300 F. with, for example, about 40 liters ofoxygen per kilogram of foots oil per hour using about 0.85 percent byweight of potassium permanganate. The reac tion is continued until theoxidation is substantially complete, for example, until the reactionmixture has a saponification number of about 250 to 300. The oxidate isthen separated, for example, by filtration.

The foots oil oxidates are characterized by a relatively low meltingpoint within the range of about 80 to 95 F., an API gravity of about to25 and a saponification number of about 200 to 325. The crude oxidateshave a saponification number of about 250 to 325. When purified byfiltration, washing with water containing hy drochloric acid and steamstripping, the purified oxidates have a melting point within the rangeof about 80 to 95 F., an API gravity of about 10 to 25 and asaponification number of about 200 to 250. Also, the acid number of thecrude oxidate is lowered from about 150 to 200 to about 100 to 150 forthe purified oxidate. The oxidates are waxy solids that are light amberto brown in color and are characterized by improved stability, good oilsolubility and good rust inhibiting properties.

Preparation of other paraffin wax oxidates, such as slack wax oxidates,to be used in the invention also can be accomplished according to knownprocesses. For example, a crystalline wax having an ASTM petrolatummelting point of about 130.l F., API gravity of 42.7, zerosaponification and acid numbers and a kinematic viscosity at 175 F. ofabout 4.932 can be oxidized to a product for use in the presentinvention by contacting the wax with oxygen, either substantially pureor in the presence of diluents such as in air. Advantageously, about 40liters of substantially pure oxygen per hour per kilogram of wax in thepresence of a water solution of about 0.5 to 1.0 weight percent of acatalyst such as potassium permanganate are used to effect theoxidation.

- Temperatures of about 100 to 200 C. and especially about 130 to 150 C.are employed. The resulting crude products advantageously are purifiedby water washing, a id ashing. and Steam stripping and upon purificationnormally evidence a saponification number of about 200 to 500, forexample 240 to 350, depending upon the degree of completion of theoxidation effected. For purposes of the present invention, it isdesirable that substantially complete oxidation be effected though, ofcourse, products having other degrees of oxidation can be employed. Atypical purified oxidized crystalline parafiin wax which can be employedin the invention has the following properties: ASTM petrolatum meltingpoint of 114 F., saponification number of 246.7, acid number of 153.0,API gravity of 23.2", and a water content of about 0.12 weight percent.

Oil-soluble aromatic sulfonates to be used in the present invention arewell-known articles of commerce. An advantageous procedure for obtainingsatisfactory sulfonates comprises sulfonating an aromatic hydrocarboncontaining petroleum fraction, such as a suitable gas oil or lubricatingoil, with a sulfonating agent such as fuming sulfuric acid or sulfurtrioxide, separating the sludge and green acids from the resulting oillayer and neutralizing the sulfonic acids contained in the oil layerwith a suitable neutralizing agent such as calcium or barium, preferablyemployed as the oxide or hydroxide. Specific conditions of contact time,temperatures, pressures, ratios of sulfonating agent to feed and thelike are known in the art.

Ammonia neutralized sulfonated bottoms from the manufacture ofdodecylbenzene constitute the preferred oil-soluble aromatic sulfonatesto be employed in this invention and are articles of commerce obtained,for example, as Bryton ammonium sulfonate from the Bryton ChemicalCompany. The materials which are sulfonated and neutralized are derivedfrom the bottoms resulting in the production of dodecylbenzene(Neolene), and specifically are the bottoms remaining afterfractionation to remove the monododecylbenzene cut from the reactionproducts of dodecene with benzene. These bottoms are wide boiling rangemixtures consisting essentially of didodecylbenzene along with otherpolyalkylated benzene molecules and olefin polymers such as lowmolecular weight polymers of dodecene. The mixture is produced byalkylating benzene with dodecene according to known procedures, forexample, by the liquid phase contacting of dodecene and benzene at about50 to 300 C., and a pressure of 5 to 50 atmospheres in the presence ofan alkylation catalyst such as aluminum chloride or sulfuric acid or thelike. The bottoms are then obtained by fractionating monododecylbenzeneand lighter constituents from the reaction mass.

The Neolene bottoms are sulfonated and neutralized with ammoniaaccording to known processes such as that described in US. Patent2,671,757 to Wisherd. Sulfonation can be accomplished by adding 20percent oleum to a charge of bottoms maintained at about 75 to F. in aMonel sulfonator. After the oleum is added, the resulting acid mass iswashed and the sulfonic acids are separated, i.e., by settling. Thesulfonated material is then neutralized by contacting with ammonia byconventional procedures. The resulting neutralized sulfonated materialis a semi-viscous fluid which is miscible in all proportions in fiuidssuch as kerosene, gasoline and low viscosity white oils and similarhydrocarbon solvents.

Solvents which can be employed in producing the con-.- centrates of theinstant invention are hydrocarbon solvents and preferably petroleumhydrocarbon solvents. Particular solvents include kerosene, toluene,xylene, aromatic petroleum fractions and extracts, and parafiinicpetroleum fractions. The ordinary refinery-produced solvents such as thevarious nap'hthas, .or reformate cuts and the like are alsoadvantageous.

As pointed out above, the compositions of the present invention areespecially useful as anti-corrosion additives ti; fi iit. its

156i 1000 barrels are'e'mployed formost purposes.

l The invention will. be illustrated further withrefere e tothefollowing examples. Itshould be understood lthat' e details disclosedare not toubie considered as limiting EXAMPLE 'I About 2200 grams of amicrocrystalline wax derived from a M s .Ws ;.1.-. as rw isgartest ter!into a reactor flask. About 1.0% by weight of potassium permanganatedissolved in about 100 ml. of water was added to the wax and the mixturewas heated-to-about 1 50; C. to remove solvent water. About 1.0% byweight of; seed, a "product from a previous run, was.- added. The ;rnixtu re was then reacted at about5g149 Cgin the nreesn ot about 0 l e spe 9 1 .pe k e mzof Wax of substantially pure oxygen. 7 Duringthecourseof 'the ea n a water layctan an ac d y Q ata t overhead,Sarnplesof the oxidate were taken periodically an t n a ien a d a dt-nu'm rs d m na ts- A sample" taken at the expiration" of three hourshad' a saponification number of 28.1 and an acid number of 11.3.

The three hour sample was cooled and then washed with HCl to removemanganese salts and then with Water to remove acid. The product wasdried by blowing with air at 80 C. Analysis of the resulting productshowed 0.20% water, 0.004% manganese, a saponification number of 23.0and an acid number of 9.64.

To demonstrate the effect of various microcrystalline wax oxidates,solutions of an oxidate of a foots oil fraction in an aromatic petroleumhydrocarbon solvent were made. The characteristics of the foots oiloxidate were:

Saponification No. 234 Acid No. 129 Pour point, F. 95 API gravity 22Flash point, F. 375

The characteristics of the aromatic petroleum hydrocarbon solventemployed, hereinafter referred to as the aromatic solvent, were:

Gravity, API 33.5 Flash, F. 123 Odor Good Appearance Bright Doctor test(ASTM D 484) Negative Mixed Aniline P.T., C. (ASTM D 611 or D Partiallyoxidized microcrystalline wax was added to g I, or solutions'fofafodtsbi] oxidate .and'ammoni'a neutralized sulfonated bottoms from themanufacture of dodecylbenzene were made by adding varying amounts of asolution of 35 weight percent footsf oil oxidate in the aromatic solventto a solution of 35 weight percent ammonia neutralized sulfouatc'dbottoms in kerosene. One percent of a substantially dehydrated partiallyoxidized microcrystalline wax hav';

im at se. esjo L ing a 'saponification number of 135 was added to eachsolution and the pour points of the resulting solutions were determined.The data, obtained are:

Table II.-.P0ur Points I l l Percent Foots Oil Oxidate Solution 1Without With N Additive Additive:

which can be expected according to the present invention.

It'is also apparent that-'thernost desirable mount. of the partiallyoxidized microcrystalline wax to beemployed in any instance isdetermined by a consideration of both the degree of oxidation of themicrocrystalline wax as evidenced by its saponification number, and theconcentration of the oxidate, i.e. foots oil oxidate, present.

To demonstrate the effect of the water content of the partially oxidizedmicrocrystalline wax on the pour point of the compositions, a solutioncontaining 30 pounds of a foots oil oxidate and 69 pounds of thearomatic petroleum solvent was made. To 10 pound samples of this solution, 0.1 pound of partially oxidized microcrystalline wax was added.The characteristics of the partially oxidized wax employed in eachsample and the pour points obtained are:

Table III.-Micr0crystalline wax oxidate Percent Pour Solution No. SapNo. Hi0 ILoiBnt,

From these data, it is clear that the water content of a partiallyoxidized wax must be limited to obtain satisfactory pour points. Thus,the high water contents of 1.58 and 3.15% were substantially withouteffect as regards pour points of the tested solutions.

Tests were conducted to determine the concentrations of oxidizedmicrocrystalline wax necessary. The oxidized microcrystalline waxemployed had a saponification number of 92; an aromatic solvent andfoots oil oxidate essentially as described in Example I were employed asa test solutions. The data obtained are:

the foots 011 oxidate solutions. The results are as fol- Table IV lows:

0 Table I.-P0ur pomts In F. cotr'lcenqw 10H 0 Weight Percent OxidizedMicrocrystalline Wax Foots Oil Pour Concentration of Foots Oxidate,Point,F.

Oil Oxidate Solutions Wt. Concentration and Saponification Number (wt.percent of oxidate) Percent of Microcrystalllne Wax oxidate 1 35 307 030 45 2.5-- 35 --15 None. 45 45 Saponification No. 23, 1% 45 30 s p ig g3 -33 23 -12 In general, with the solut1ons containing a larger configggg gg gfi 3: 51:1111 10 centration of the foots oil oxidate, largerquantities of the partially oxidized microcrystalline wax are neededEach oxidate contalnedless than 1.0 weight percent water. 15 to obtain yElven P Point Ieducmm- W5 oxidized microcrystalline wax, i.e. on theorder of 10 percent or more, did not effect a pour point lowering.

I claim:

1. A composition consisting essentially of about to 65 weight percent ofa foots oil oxidate, about 50 to 95 weight percent of a hydrocarbonsolvent and about 0.1 to 4 weight percent of a substantially dehydratedpartially oxidized microcrystalline wax having a saponification numberof about to 150.

2. A composition consisting essentially of about 50 to 95 weight percentof an aromatic hydrocarbon solvent, about 5 to 65 weight percent of anoxidate of a foots oil fraction and about 0.1 to 4 weight percent of asubstantially dehydrated partially oxidized microcrystalline wax havinga saponification number of about 10 to 150, said foots oil oxidatehaving a melting point of about 80 to 95 R, an API gravity of about 10to 25 and a saponification number of about 200 to 325.

3. A composition consisting essentially of about 5 to weight percent ofa foots oil oxidate, about 15 to 30 weight percent of an oil-solublearomatic snlfonate, about 50 to 80 weight percent of a hydrocarbonsolvent, and 0.1 to 4 weight percent of a substantially dehydratedpartially oxidized microcrystalline wax having a saponification numberof about 10 to 150.

have shown, however, that large amounts of the partially 4. Acomposition consisting essentially of about 5 to 15 weight percent of afoots oil oxidate, about 15 to weight percent of an ammonia neutralizedsulfonated bottoms from the manufacture of dodecylbenzene, about toweight percent of kerosene and about 0.1 to 4 weight percent of asubstantially dehydrated partially oxidized microcrystalline wax havinga saponification number of about 10 to 150, said foots oil oxidatehaving a melting point of about 80 to R, an API gravity of about 10 to25 and a saponification number of about 200 to 325.

References Cited in the file of this patent UNITED STATES PATENTS2,209,165 Martin et al. July 23, 1940 2,632,694 Watkins Mar. 24, 19532,667,408 Kleinholz Jan. 26, 1954 2,671,051 Moore Mar. 2, 1954 2,671,757Wisherd Mar. 9, 1954 2,671,759 Eckert Mar. 9, 1954 2,682,553 Kirk June29, 1954 2,705,241 McKinley Mar. 29, 1955 2,727,005 McKinley et a1. Dec.13, 1955

1.
 2. A COMPOSITION CONSISTING ESSENTIALLY OF ABOUT 50 TO 95 WEIGHTPERCENT OF AN AROMATIC HYDROCARBON SOLVENT, ABOUT 5 TO 65 WEIGHT PERCENTOF AN OXIDATE OF A FOOTS OIL FRACTION AND ABOUT 0.1 TO 4 WEIGHT PERCENTOF A SUBSTANTIALLY DEHYDRATED PARTIALLY OXIDIZED MICROCRYSTALLINE WAXHAVING A SAPONIFICATION NUMBER OF ABOUT 10 TO 150, SAID FOOTS OILOXIDATE HAVING A MELTING POINT OF ABOUT 80 TO 95*F., AN API GRAVITY OFABOUT 10 TO 25 AND A SAPONIFICATION NUMBER OF ABOUT 200 TO 325.